#!/usr/bin/python
# -*- coding: utf-8 -*-

# Copyright: (c) 2019, Andrew Klychkov (@Andersson007) <aaklychkov@mail.ru>
# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)

from __future__ import absolute_import, division, print_function
__metaclass__ = type

ANSIBLE_METADATA = {
    'metadata_version': '1.1',
    'status': ['preview'],
    'supported_by': 'community'
}

DOCUMENTATION = r'''
---
module: postgresql_info
short_description: Gather information about PostgreSQL servers
description:
- Gathers information about PostgreSQL servers.
version_added: '2.8'
options:
  filter:
    description:
    - Limit the collected information by comma separated string or YAML list.
    - Allowable values are C(version),
      C(databases), C(settings), C(tablespaces), C(roles),
      C(replications), C(repl_slots).
    - By default, collects all subsets.
    - You can use shell-style (fnmatch) wildcard to pass groups of values (see Examples).
    - You can use '!' before value (for example, C(!settings)) to exclude it from the information.
    - If you pass including and excluding values to the filter, for example, I(filter=!settings,ver),
      the excluding values will be ignored.
    type: list
  db:
    description:
    - Name of database to connect.
    type: str
    aliases:
    - login_db
  session_role:
    description:
    - Switch to session_role after connecting. The specified session_role must
      be a role that the current login_user is a member of.
    - Permissions checking for SQL commands is carried out as though
      the session_role were the one that had logged in originally.
    type: str
notes:
- The default authentication assumes that you are either logging in as or
  sudo'ing to the postgres account on the host.
- login_user or session_role must be able to read from pg_authid.
- To avoid "Peer authentication failed for user postgres" error,
  use postgres user as a I(become_user).
- This module uses psycopg2, a Python PostgreSQL database adapter. You must
  ensure that psycopg2 is installed on the host before using this module. If
  the remote host is the PostgreSQL server (which is the default case), then
  PostgreSQL must also be installed on the remote host. For Ubuntu-based
  systems, install the postgresql, libpq-dev, and python-psycopg2 packages
  on the remote host before using this module.
requirements: [ psycopg2 ]
author:
- Andrew Klychkov (@Andersson007)
extends_documentation_fragment: postgres
'''

EXAMPLES = r'''
# Display info from postgres hosts.
# ansible postgres -m postgresql_info

# Display only databases and roles info from all hosts using shell-style wildcards:
# ansible all -m postgresql_info -a 'filter=dat*,rol*'

# Display only replications and repl_slots info from standby hosts using shell-style wildcards:
# ansible standby -m postgresql_info -a 'filter=repl*'

# Display all info from databases hosts except settings:
# ansible databases -m postgresql_info -a 'filter=!settings'

- name: Collect PostgreSQL version and extensions
  become: yes
  become_user: postgres
  postgresql_info:
    filter: ver*,ext*

- name: Collect all info except settings and roles
  become: yes
  become_user: postgres
  postgresql_info:
    filter: "!settings,!roles"

# On FreeBSD with PostgreSQL 9.5 version and lower use pgsql user to become
# and pass "postgres" as a database to connect to
- name: Collect tablespaces and repl_slots info
  become: yes
  become_user: pgsql
  postgresql_info:
    db: postgres
    filter:
    - tablesp*
    - repl_sl*

- name: Collect all info except databases
  become: yes
  become_user: postgres
  postgresql_info:
    filter:
    - "!databases"
'''

RETURN = r'''
version:
  description: Database server version U(https://www.postgresql.org/support/versioning/).
  returned: always
  type: dict
  sample: { "version": { "major": 10, "minor": 6 } }
  contains:
    major:
      description: Major server version.
      returned: always
      type: int
      sample: 11
    minor:
      description: Minor server version.
      returned: always
      type: int
      sample: 1
databases:
  description: Information about databases.
  returned: always
  type: dict
  sample:
  - { "postgres": { "access_priv": "", "collate": "en_US.UTF-8",
  "ctype": "en_US.UTF-8", "encoding": "UTF8", "owner": "postgres", "size": "7997 kB" } }
  contains:
    database_name:
      description: Database name.
      returned: always
      type: dict
      sample: template1
      contains:
        access_priv:
          description: Database access privileges.
          returned: always
          type: str
          sample: "=c/postgres_npostgres=CTc/postgres"
        collate:
          description:
          - Database collation U(https://www.postgresql.org/docs/current/collation.html).
          returned: always
          type: str
          sample: en_US.UTF-8
        ctype:
          description:
          - Database LC_CTYPE U(https://www.postgresql.org/docs/current/multibyte.html).
          returned: always
          type: str
          sample: en_US.UTF-8
        encoding:
          description:
          - Database encoding U(https://www.postgresql.org/docs/current/multibyte.html).
          returned: always
          type: str
          sample: UTF8
        owner:
          description:
          - Database owner U(https://www.postgresql.org/docs/current/sql-createdatabase.html).
          returned: always
          type: str
          sample: postgres
        size:
          description: Database size in bytes.
          returned: always
          type: str
          sample: 8189415
        extensions:
          description:
          - Extensions U(https://www.postgresql.org/docs/current/sql-createextension.html).
          returned: always
          type: dict
          sample:
          - { "plpgsql": { "description": "PL/pgSQL procedural language",
            "extversion": { "major": 1, "minor": 0 } } }
          contains:
            extdescription:
              description: Extension description.
              returned: if existent
              type: str
              sample: PL/pgSQL procedural language
            extversion:
              description: Extension description.
              returned: always
              type: dict
              contains:
              major:
                description: Extension major version.
                returned: always
                type: int
                sample: 1
              minor:
                description: Extension minor version.
                returned: always
                type: int
                sample: 0
            nspname:
              description: Namespace where the extension is.
              returned: always
              type: str
              sample: pg_catalog
        languages:
          description: Procedural languages U(https://www.postgresql.org/docs/current/xplang.html).
          returned: always
          type: dict
          sample: { "sql": { "lanacl": "", "lanowner": "postgres" } }
          contains:
            lanacl:
              description:
              - Language access privileges
                U(https://www.postgresql.org/docs/current/catalog-pg-language.html).
              returned: always
              type: str
              sample: "{postgres=UC/postgres,=U/postgres}"
            lanowner:
              description:
              - Language owner U(https://www.postgresql.org/docs/current/catalog-pg-language.html).
              returned: always
              type: str
              sample: postgres
        namespaces:
          description:
          - Namespaces (schema) U(https://www.postgresql.org/docs/current/sql-createschema.html).
          returned: always
          type: dict
          sample: { "pg_catalog": { "nspacl": "{postgres=UC/postgres,=U/postgres}", "nspowner": "postgres" } }
          contains:
            nspacl:
              description:
              - Access privileges U(https://www.postgresql.org/docs/current/catalog-pg-namespace.html).
              returned: always
              type: str
              sample: "{postgres=UC/postgres,=U/postgres}"
            nspowner:
              description:
              - Schema owner U(https://www.postgresql.org/docs/current/catalog-pg-namespace.html).
              returned: always
              type: str
              sample: postgres
repl_slots:
  description:
  - Replication slots (available in 9.4 and later)
    U(https://www.postgresql.org/docs/current/catalog-pg-replication-slots.html).
  returned: if existent
  type: dict
  sample: { "slot0": { "active": false, "database": null, "plugin": null, "slot_type": "physical" } }
  contains:
    active:
      description:
      - True means that a receiver has connected to it, and it is currently reserving archives.
      returned: always
      type: bool
      sample: true
    database:
      description: Database name this slot is associated with, or null.
      returned: always
      type: str
      sample: acme
    plugin:
      description:
      - Base name of the shared object containing the output plugin
        this logical slot is using, or null for physical slots.
      returned: always
      type: str
      sample: pgoutput
    slot_type:
      description: The slot type - physical or logical.
      returned: always
      type: str
      sample: logical
replications:
  description:
  - Information about the current replications by process PIDs
    U(https://www.postgresql.org/docs/current/monitoring-stats.html#MONITORING-STATS-VIEWS-TABLE).
  returned: if pg_stat_replication view existent
  type: dict
  sample:
  - { 76580: { "app_name": "standby1", "backend_start": "2019-02-03 00:14:33.908593+03",
    "client_addr": "10.10.10.2", "client_hostname": "", "state": "streaming", "usename": "postgres" } }
  contains:
    usename:
      description:
      - Name of the user logged into this WAL sender process ('usename' is a column name in pg_stat_replication view).
      returned: always
      type: str
      sample: replication_user
    app_name:
      description: Name of the application that is connected to this WAL sender.
      returned: if existent
      type: str
      sample: acme_srv
    client_addr:
      description:
      - IP address of the client connected to this WAL sender.
      - If this field is null, it indicates that the client is connected
        via a Unix socket on the server machine.
      returned: always
      type: str
      sample: 10.0.0.101
    client_hostname:
      description:
      - Host name of the connected client, as reported by a reverse DNS lookup of client_addr.
      - This field will only be non-null for IP connections, and only when log_hostname is enabled.
      returned: always
      type: str
      sample: dbsrv1
    backend_start:
      description: Time when this process was started, i.e., when the client connected to this WAL sender.
      returned: always
      type: str
      sample: "2019-02-03 00:14:33.908593+03"
    state:
      description: Current WAL sender state.
      returned: always
      type: str
      sample: streaming
tablespaces:
  description:
  - Information about tablespaces U(https://www.postgresql.org/docs/current/catalog-pg-tablespace.html).
  returned: always
  type: dict
  sample:
  - { "test": { "spcacl": "{postgres=C/postgres,andreyk=C/postgres}", "spcoptions": [ "seq_page_cost=1" ],
    "spcowner": "postgres" } }
  contains:
    spcacl:
      description: Tablespace access privileges.
      returned: always
      type: str
      sample: "{postgres=C/postgres,andreyk=C/postgres}"
    spcoptions:
      description: Tablespace-level options.
      returned: always
      type: list
      sample: [ "seq_page_cost=1" ]
    spcowner:
      description: Owner of the tablespace.
      returned: always
      type: str
      sample: test_user
roles:
  description:
  - Information about roles U(https://www.postgresql.org/docs/current/user-manag.html).
  returned: always
  type: dict
  sample:
  - { "test_role": { "canlogin": true, "member_of": [ "user_ro" ], "superuser": false,
    "valid_until": "9999-12-31T23:59:59.999999+00:00" } }
  contains:
    canlogin:
      description: Login privilege U(https://www.postgresql.org/docs/current/role-attributes.html).
      returned: always
      type: bool
      sample: true
    member_of:
      description:
      - Role membership U(https://www.postgresql.org/docs/current/role-membership.html).
      returned: always
      type: list
      sample: [ "read_only_users" ]
    superuser:
      description: User is a superuser or not.
      returned: always
      type: bool
      sample: false
    valid_until:
      description:
      - Password expiration date U(https://www.postgresql.org/docs/current/sql-alterrole.html).
      returned: always
      type: str
      sample: "9999-12-31T23:59:59.999999+00:00"
pending_restart_settings:
  description:
  - List of settings that are pending restart to be set.
  returned: always
  type: list
  sample: [ "shared_buffers" ]
settings:
  description:
  - Information about run-time server parameters
    U(https://www.postgresql.org/docs/current/view-pg-settings.html).
  returned: always
  type: dict
  sample:
  - { "work_mem": { "boot_val": "4096", "context": "user", "max_val": "2147483647",
    "min_val": "64", "setting": "8192", "sourcefile": "/var/lib/pgsql/10/data/postgresql.auto.conf",
    "unit": "kB", "vartype": "integer", "val_in_bytes": 4194304 } }
  contains:
    setting:
      description: Current value of the parameter.
      returned: always
      type: str
      sample: 49152
    unit:
      description: Implicit unit of the parameter.
      returned: always
      type: str
      sample: kB
    boot_val:
      description:
      - Parameter value assumed at server startup if the parameter is not otherwise set.
      returned: always
      type: str
      sample: 4096
    min_val:
      description:
      - Minimum allowed value of the parameter (null for non-numeric values).
      returned: always
      type: str
      sample: 64
    max_val:
      description:
      - Maximum allowed value of the parameter (null for non-numeric values).
      returned: always
      type: str
      sample: 2147483647
    sourcefile:
      description:
      - Configuration file the current value was set in.
      - Null for values set from sources other than configuration files,
        or when examined by a user who is neither a superuser or a member of pg_read_all_settings.
      - Helpful when using include directives in configuration files.
      returned: always
      type: str
      sample: /var/lib/pgsql/10/data/postgresql.auto.conf
    context:
      description:
      - Context required to set the parameter's value.
      - For more information see U(https://www.postgresql.org/docs/current/view-pg-settings.html).
      returned: always
      type: str
      sample: user
    vartype:
      description:
      - Parameter type (bool, enum, integer, real, or string).
      returned: always
      type: str
      sample: integer
    val_in_bytes:
      description:
      - Current value of the parameter in bytes.
      returned: if supported
      type: int
      sample: 2147483647
    pretty_val:
      description:
      - Value presented in the pretty form.
      returned: always
      type: str
      sample: 2MB
    pending_restart:
      description:
      - True if the value has been changed in the configuration file but needs a restart; or false otherwise.
      - Returns only if C(settings) is passed.
      returned: always
      type: bool
      sample: false
'''

from fnmatch import fnmatch

try:
    from psycopg2.extras import DictCursor
except ImportError:
    # psycopg2 is checked by connect_to_db()
    # from ansible.module_utils.postgres
    pass

from ansible.module_utils.basic import AnsibleModule
from ansible.module_utils.postgres import (
    connect_to_db,
    get_conn_params,
    postgres_common_argument_spec,
)
from ansible.module_utils._text import to_native


# ===========================================
# PostgreSQL module specific support methods.
#

class PgDbConn(object):

    """Auxiliary class for working with PostgreSQL connection objects.

    Arguments:
        module (AnsibleModule): Object of AnsibleModule class that
            contains connection parameters.
    """

    def __init__(self, module):
        self.module = module
        self.db_conn = None
        self.cursor = None

    def connect(self):
        """Connect to a PostgreSQL database and return a cursor object.

        Note: connection parameters are passed by self.module object.
        """
        conn_params = get_conn_params(self.module, self.module.params, warn_db_default=False)
        self.db_conn = connect_to_db(self.module, conn_params)
        return self.db_conn.cursor(cursor_factory=DictCursor)

    def reconnect(self, dbname):
        """Reconnect to another database and return a PostgreSQL cursor object.

        Arguments:
            dbname (string): Database name to connect to.
        """
        self.db_conn.close()

        self.module.params['database'] = dbname
        return self.connect()


class PgClusterInfo(object):

    """Class for collection information about a PostgreSQL instance.

    Arguments:
        module (AnsibleModule): Object of AnsibleModule class.
        db_conn_obj (psycopg2.connect): PostgreSQL connection object.
    """

    def __init__(self, module, db_conn_obj):
        self.module = module
        self.db_obj = db_conn_obj
        self.cursor = db_conn_obj.connect()
        self.pg_info = {
            "version": {},
            "tablespaces": {},
            "databases": {},
            "replications": {},
            "repl_slots": {},
            "settings": {},
            "roles": {},
            "pending_restart_settings": [],
        }

    def collect(self, val_list=False):
        """Collect information based on 'filter' option."""
        subset_map = {
            "version": self.get_pg_version,
            "tablespaces": self.get_tablespaces,
            "databases": self.get_db_info,
            "replications": self.get_repl_info,
            "repl_slots": self.get_rslot_info,
            "settings": self.get_settings,
            "roles": self.get_role_info,
        }

        incl_list = []
        excl_list = []
        # Notice: incl_list and excl_list
        # don't make sense together, therefore,
        # if incl_list is not empty, we collect
        # only values from it:
        if val_list:
            for i in val_list:
                if i[0] != '!':
                    incl_list.append(i)
                else:
                    excl_list.append(i.lstrip('!'))

            if incl_list:
                for s in subset_map:
                    for i in incl_list:
                        if fnmatch(s, i):
                            subset_map[s]()
                            break
            elif excl_list:
                found = False
                # Collect info:
                for s in subset_map:
                    for e in excl_list:
                        if fnmatch(s, e):
                            found = True

                    if not found:
                        subset_map[s]()
                    else:
                        found = False

        # Default behaviour, if include or exclude is not passed:
        else:
            # Just collect info for each item:
            for s in subset_map:
                subset_map[s]()

        return self.pg_info

    def get_tablespaces(self):
        """Get information about tablespaces."""
        # Check spcoption exists:
        opt = self.__exec_sql("SELECT column_name "
                              "FROM information_schema.columns "
                              "WHERE table_name = 'pg_tablespace' "
                              "AND column_name = 'spcoptions'")

        if not opt:
            query = ("SELECT s.spcname, a.rolname, s.spcacl "
                     "FROM pg_tablespace AS s "
                     "JOIN pg_authid AS a ON s.spcowner = a.oid")
        else:
            query = ("SELECT s.spcname, a.rolname, s.spcacl, s.spcoptions "
                     "FROM pg_tablespace AS s "
                     "JOIN pg_authid AS a ON s.spcowner = a.oid")

        res = self.__exec_sql(query)
        ts_dict = {}
        for i in res:
            ts_name = i[0]
            ts_info = dict(
                spcowner=i[1],
                spcacl=i[2] if i[2] else '',
            )
            if opt:
                ts_info['spcoptions'] = i[3] if i[3] else []

            ts_dict[ts_name] = ts_info

        self.pg_info["tablespaces"] = ts_dict

    def get_ext_info(self):
        """Get information about existing extensions."""
        # Check that pg_extension exists:
        res = self.__exec_sql("SELECT EXISTS (SELECT 1 FROM "
                              "information_schema.tables "
                              "WHERE table_name = 'pg_extension')")
        if not res[0][0]:
            return True

        query = ("SELECT e.extname, e.extversion, n.nspname, c.description "
                 "FROM pg_catalog.pg_extension AS e "
                 "LEFT JOIN pg_catalog.pg_namespace AS n "
                 "ON n.oid = e.extnamespace "
                 "LEFT JOIN pg_catalog.pg_description AS c "
                 "ON c.objoid = e.oid "
                 "AND c.classoid = 'pg_catalog.pg_extension'::pg_catalog.regclass")
        res = self.__exec_sql(query)
        ext_dict = {}
        for i in res:
            ext_ver = i[1].split('.')

            ext_dict[i[0]] = dict(
                extversion=dict(
                    major=int(ext_ver[0]),
                    minor=int(ext_ver[1]),
                ),
                nspname=i[2],
                description=i[3],
            )

        return ext_dict

    def get_role_info(self):
        """Get information about roles (in PgSQL groups and users are roles)."""
        query = ("SELECT r.rolname, r.rolsuper, r.rolcanlogin, "
                 "r.rolvaliduntil, "
                 "ARRAY(SELECT b.rolname "
                 "FROM pg_catalog.pg_auth_members AS m "
                 "JOIN pg_catalog.pg_roles AS b ON (m.roleid = b.oid) "
                 "WHERE m.member = r.oid) AS memberof "
                 "FROM pg_catalog.pg_roles AS r "
                 "WHERE r.rolname !~ '^pg_'")

        res = self.__exec_sql(query)
        rol_dict = {}
        for i in res:
            rol_dict[i[0]] = dict(
                superuser=i[1],
                canlogin=i[2],
                valid_until=i[3] if i[3] else '',
                member_of=i[4] if i[4] else [],
            )

        self.pg_info["roles"] = rol_dict

    def get_rslot_info(self):
        """Get information about replication slots if exist."""
        # Check that pg_replication_slots exists:
        res = self.__exec_sql("SELECT EXISTS (SELECT 1 FROM "
                              "information_schema.tables "
                              "WHERE table_name = 'pg_replication_slots')")
        if not res[0][0]:
            return True

        query = ("SELECT slot_name, plugin, slot_type, database, "
                 "active FROM pg_replication_slots")
        res = self.__exec_sql(query)

        # If there is no replication:
        if not res:
            return True

        rslot_dict = {}
        for i in res:
            rslot_dict[i[0]] = dict(
                plugin=i[1],
                slot_type=i[2],
                database=i[3],
                active=i[4],
            )

        self.pg_info["repl_slots"] = rslot_dict

    def get_settings(self):
        """Get server settings."""
        # Check pending restart column exists:
        pend_rest_col_exists = self.__exec_sql("SELECT 1 FROM information_schema.columns "
                                               "WHERE table_name = 'pg_settings' "
                                               "AND column_name = 'pending_restart'")
        if not pend_rest_col_exists:
            query = ("SELECT name, setting, unit, context, vartype, "
                     "boot_val, min_val, max_val, sourcefile "
                     "FROM pg_settings")
        else:
            query = ("SELECT name, setting, unit, context, vartype, "
                     "boot_val, min_val, max_val, sourcefile, pending_restart "
                     "FROM pg_settings")

        res = self.__exec_sql(query)

        set_dict = {}
        for i in res:
            val_in_bytes = None
            setting = i[1]
            if i[2]:
                unit = i[2]
            else:
                unit = ''

            if unit == 'kB':
                val_in_bytes = int(setting) * 1024

            elif unit == '8kB':
                val_in_bytes = int(setting) * 1024 * 8

            elif unit == 'MB':
                val_in_bytes = int(setting) * 1024 * 1024

            if val_in_bytes is not None and val_in_bytes < 0:
                val_in_bytes = 0

            setting_name = i[0]
            pretty_val = self.__get_pretty_val(setting_name)

            pending_restart = None
            if pend_rest_col_exists:
                pending_restart = i[9]

            set_dict[setting_name] = dict(
                setting=setting,
                unit=unit,
                context=i[3],
                vartype=i[4],
                boot_val=i[5] if i[5] else '',
                min_val=i[6] if i[6] else '',
                max_val=i[7] if i[7] else '',
                sourcefile=i[8] if i[8] else '',
                pretty_val=pretty_val,
            )
            if val_in_bytes is not None:
                set_dict[setting_name]['val_in_bytes'] = val_in_bytes

            if pending_restart is not None:
                set_dict[setting_name]['pending_restart'] = pending_restart
                if pending_restart:
                    self.pg_info["pending_restart_settings"].append(setting_name)

        self.pg_info["settings"] = set_dict

    def get_repl_info(self):
        """Get information about replication if the server is a master."""
        # Check that pg_replication_slots exists:
        res = self.__exec_sql("SELECT EXISTS (SELECT 1 FROM "
                              "information_schema.tables "
                              "WHERE table_name = 'pg_stat_replication')")
        if not res[0][0]:
            return True

        query = ("SELECT r.pid, a.rolname, r.application_name, r.client_addr, "
                 "r.client_hostname, r.backend_start::text, r.state "
                 "FROM pg_stat_replication AS r "
                 "JOIN pg_authid AS a ON r.usesysid = a.oid")
        res = self.__exec_sql(query)

        # If there is no replication:
        if not res:
            return True

        repl_dict = {}
        for i in res:
            repl_dict[i[0]] = dict(
                usename=i[1],
                app_name=i[2] if i[2] else '',
                client_addr=i[3],
                client_hostname=i[4] if i[4] else '',
                backend_start=i[5],
                state=i[6],
            )

        self.pg_info["replications"] = repl_dict

    def get_lang_info(self):
        """Get information about current supported languages."""
        query = ("SELECT l.lanname, a.rolname, l.lanacl "
                 "FROM pg_language AS l "
                 "JOIN pg_authid AS a ON l.lanowner = a.oid")
        res = self.__exec_sql(query)
        lang_dict = {}
        for i in res:
            lang_dict[i[0]] = dict(
                lanowner=i[1],
                lanacl=i[2] if i[2] else '',
            )

        return lang_dict

    def get_namespaces(self):
        """Get information about namespaces."""
        query = ("SELECT n.nspname, a.rolname, n.nspacl "
                 "FROM pg_catalog.pg_namespace AS n "
                 "JOIN pg_authid AS a ON a.oid = n.nspowner")
        res = self.__exec_sql(query)

        nsp_dict = {}
        for i in res:
            nsp_dict[i[0]] = dict(
                nspowner=i[1],
                nspacl=i[2] if i[2] else '',
            )

        return nsp_dict

    def get_pg_version(self):
        """Get major and minor PostgreSQL server version."""
        query = "SELECT version()"
        raw = self.__exec_sql(query)[0][0]
        raw = raw.split()[1].split('.')
        self.pg_info["version"] = dict(
            major=int(raw[0]),
            minor=int(raw[1]),
        )

    def get_db_info(self):
        """Get information about the current database."""
        # Following query returns:
        # Name, Owner, Encoding, Collate, Ctype, Access Priv, Size
        query = ("SELECT d.datname, "
                 "pg_catalog.pg_get_userbyid(d.datdba), "
                 "pg_catalog.pg_encoding_to_char(d.encoding), "
                 "d.datcollate, "
                 "d.datctype, "
                 "pg_catalog.array_to_string(d.datacl, E'\n'), "
                 "CASE WHEN pg_catalog.has_database_privilege(d.datname, 'CONNECT') "
                 "THEN pg_catalog.pg_database_size(d.datname)::text "
                 "ELSE 'No Access' END, "
                 "t.spcname "
                 "FROM pg_catalog.pg_database AS d "
                 "JOIN pg_catalog.pg_tablespace t ON d.dattablespace = t.oid "
                 "WHERE d.datname != 'template0'")

        res = self.__exec_sql(query)

        db_dict = {}
        for i in res:
            db_dict[i[0]] = dict(
                owner=i[1],
                encoding=i[2],
                collate=i[3],
                ctype=i[4],
                access_priv=i[5] if i[5] else '',
                size=i[6],
            )

        for datname in db_dict:
            self.cursor = self.db_obj.reconnect(datname)
            db_dict[datname]['namespaces'] = self.get_namespaces()
            db_dict[datname]['extensions'] = self.get_ext_info()
            db_dict[datname]['languages'] = self.get_lang_info()

        self.pg_info["databases"] = db_dict

    def __get_pretty_val(self, setting):
        """Get setting's value represented by SHOW command."""
        return self.__exec_sql("SHOW %s" % setting)[0][0]

    def __exec_sql(self, query):
        """Execute SQL and return the result."""
        try:
            self.cursor.execute(query)
            res = self.cursor.fetchall()
            if res:
                return res
        except Exception as e:
            self.module.fail_json(msg="Cannot execute SQL '%s': %s" % (query, to_native(e)))
            self.cursor.close()
        return False

# ===========================================
# Module execution.
#


def main():
    argument_spec = postgres_common_argument_spec()
    argument_spec.update(
        db=dict(type='str', aliases=['login_db']),
        filter=dict(type='list'),
        session_role=dict(type='str'),
    )
    module = AnsibleModule(
        argument_spec=argument_spec,
        supports_check_mode=True,
    )

    filter_ = module.params["filter"]

    db_conn_obj = PgDbConn(module)

    # Do job:
    pg_info = PgClusterInfo(module, db_conn_obj)

    module.exit_json(**pg_info.collect(filter_))


if __name__ == '__main__':
    main()
